The present invention relates to a cylinder head and piston configuration of an internal combustion engine, and more particularly relates to such a configuration which incorporates a squish area.
In designing combustion chamber configurations, the requirements of good fuel consumption, stable combustion, and good exhaust gas quality must all be considered. In order to reduce fuel consumption, it is effective to increase the compression ratio. However, in the case of a usual combustion chamber, increase of the compression ratio is limited by the occurrence of abnormal combustion such as knocking. In order to achieve stable combustion, it is effective to increase the turbulence of the mixture gas in the combustion chamber, and to make the combustion chamber compact. A conventional wedge-shaped combustion chamber provides quite good combustion characteristics. However, as a matter of experience, it is found that if an engine with a wedge-shaped combustion chamber is operated with a rather lean air-fuel mixture, or with exhaust gas recirculation, in order to improve the qualities of the exhaust gases and reduce the emission of harmful exhaust gas components, combustion becomes disturbed and uneven, and the operability of the engine deteriorates so far that, if the engine, for example, is used in a vehicle, the drivability of the vehicle is poor.